Ion transport through membrane

The ion transport through membrane systems can be studied in two forms ... 

KoxY = exP [-F ( Ox/Red) (OxY/RedY) ) / ]. Here, E oxY/RedY) the formal potential of the redox couple OxY/RedY. Electrochemical switching has received much attention with respect to anion and cation recognition, analytical applications, biomimetics of ion transport through membranes, and generally molecular recognition. 

Ion pumps (physiological) - ion transport through membranes and ion channels... 

Cooper, K., Jakobsson, E. and Wolynes, P. (1985) The Theory of Ion Transport Through Membrane Channels. Prog. Biophys. Mol. Biol., 46, 51-96 (1985). Hille, B. (2001) Ion Channels of Excitable Membranes, 3rd edn, Sinauer Associates, Sunderland, MA. 

G. Boheim, S. Gelfert, G. Jung and G. Menestrina, in Ion Transport through Membranes (eds... 

There are many methods for the measurement of ion transport through membranes. We shall describe here two physical methods that directly measure ion flow in black lipid membranes, large vesicular, and cell membranes as well as a method that works with a large population of vesicles of any size and entrapped fluorescence dyes. 

Caledonin, a modified peptide isolated from the marine tunicate Didemnum ro-driguesi. The amino group of the central Phe residue is linked with (S)-3-amino-5-mercaptopentanoic acid, whereas the carboxy function is connected with a six-membered cycloguanidine ring system bearing a n-octyl side chain. Caledonin is a natural peptide bolaphile capable of com-plexing Zn + and Cu+ ions, and may also be involved in ion transport through membranes [M. J. Vazquez et al.. Tetrahedron Lett. 1995, 36, 8853]. 

II. ION TRANSPORT THROUGH MEMBRANES IN PRESENCE OF SUFFICIENT ELECTROLYTES... 

Bystrov et al. (33) have compared the NMR spectra of valinomycin, beauvericin, and antamanide with those of their Na+ and K+ complexes. These compounds are being widely studied as tools in the understanding of processes associated with ion transport through membranes. The ion in these complexes is located in a central cavity and is held in place by ion-dipole interactions between carbonyls oriented toward the center of the cavity and the metal ion. The ion-dipole interaction should bring about a downfield shift of the carbonyl resonance. 

Figure 19. Bacterial representatives of active ion-transport through membranes, modeling phase-transition strategies of protein information function lines stereo-presentation of a CPK-valinomycin movie , mediating by highly sophisticated biomesogenic interplays a K -ion membrane passage [7 a, 33 p, q, 35].

Aguilella, V., Belaya, M., and Levadny, V., Ion transport through membranes with soft interfaces, the influence of the polar zone thickness. Thin Solid Film, 272 (1), 10 14, 1996. 

Such membranes prevent the passage of Na+ and K+ ions, the process important for the transmission of electrical signals between lining cells. Being hydrophilic, these ions cannot pass through the hydrophobic layer of the membrane. For ion transport through membranes, the cells have developed special catalytic systems which require specific groups of enzymes. 

It wasn t until the late 50 s that a renewed interest occurred in developing techniques for vivo measurements of electrochemical phenomena (other than in areas related to ion transport through membranes). Increased refinement and the sensitivity necessary for biological studies also evolved. 

There still remain other examples of the science of electrochemistry deeply involved in technological functions. Electrochemical machining was a key to turbine bucket manufacturing for aircraft engines, here the science elicited in the study of corrosion processes in conducting media paid off handsomely. More recently applications in the health field of our experience with ion transport through membranes has been fruitful. This line may well have started with the electrochemists long time interest in how the electric eel functions. 

Ion transport through membranes is central to the operation of many biological processes, particularly signal transduction in neurons, and we need to be equipped to describe ion migration quantitatively. 

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